Auteur(s): A. Abdo A., Ackermann M., Ajello M., Anderson B., B. Atwood W., Axelsson M., Baldini L., Ballet J., Barbiellini G., Bruel P., Casandjian J.M., Cohen-Tanugi J., Dumora D., Farnier C., Fegan S.J., Giebels B., Grenier I.A., Grondin M.H., Guillemot L., Knödlseder J., Lott B., Nuss E., Parent D., Pelassa V., Piron F., Reposeur T., Sanchez D., Smith D. A., Starck J.-L., Vilchez N.
(Article) Publié:
Physical Review Letters, vol. 103 p.251101 (2009)
Texte intégral en Openaccess : 
Ref HAL: in2p3-00446920_v1
Ref Arxiv: 0912.0973
DOI: 10.1103/PhysRevLett.103.251101
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
156 citations
Résumé:
The diffuse Galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess gamma-ray emission > 1 GeV relative to diffuse Galactic gamma-ray emission models consistent with directly measured CR spectra (the so-called ``EGRET GeV excess''). The excess emission was observed in all directions on the sky, and a variety of explanations have been proposed, including beyond-the-Standard-Model scenarios like annihilating or decaying dark matter. The Large Area Telescope (LAT) instrument on the Fermi Gamma-ray Space Telescope has measured the diffuse gamma-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements of the diffuse gamma-ray emission for energies 100 MeV to 10 GeV and Galactic latitudes 10 deg. <= |b| <= 20 deg. The LAT spectrum for this region of the sky is well reproduced by a diffuse Galactic gamma-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.
Commentaires: 2 figures, 1 table, accepted by Physical Review Letters, available online Dec. 18th, 2009